I use 1 USB hd or flash drive with 3 partiions, swap, optware(ext2) and hddata (ntfs). Whenever, I want to retrieve data from hddata, I would simply umount in the GUI. I notice that said device already dismounted but not reflected in the GUI. I check this using samba to check if hddata is still mounted and it appears not mounted.

You only need the killall. The other things will be cleaned up during the unmount processing. You should not do them!

There is more stuff going on under the sheets than you are aware of.
The killall will return immediately — it does NOT wait until transmission-daemon has terminated. In fact, transmission-daemon can take anywhere from 5 to 30 seconds (or more) to terminate cleanly. It does a lot of cleanup & notify work on the way down. If you flatout kill it with kill -9, it will have to recheck every file the next time it comes up. Be prepared for this to take several hours.

Linux does a lot of fancy-dancing when it [tries to] unmount a filesystem. Tomato knows about that and works with Linux to get things unmounted cleanly and with as few side-effects as possible in unusual cases. If you do your own umount's, all that work is obviated. So don't do it. Just do the killall and let Tomato do it's thing.

In fact, what you should have is that killall line in an autostop file in the root directory of the disk, instead of in "run before unmounting". An autostop file is the converse of an autorun file. As such, it is specific to that particular disk, regardless of how many disks you have plugged in and how many routers you may move the disk to.

Mounting and unmounting poses no problem issues so far. It was so smooth. Easy to unmount and mount again. Need to do umounting to connect usb harddisk to win7 for fastest data retrieval from time to time. Then, I would connect back to tomato router and do mounting. It works flawlessly, I did a lot of repeating unmount and mount clicking procedures with no problem issue. Also, tested everytime the effect using top for any side effects, none so far.
Here is my script: